#include <bits/stdc++.h>using namespace std;
int main()
{int a,b,p,ans;while(cin>>a>>b>>p){ans=0;ans=a+(p-1)*(b-a);printf("%d\n",ans);}return 0;
}

#include <bits/stdc++.h>using namespace std;
typedef long long int ll;
ll ex_gcd(ll a,ll b,ll &x,ll &y)
{if(b==0){x=1;y=0;return a;}ll r=ex_gcd(b,a%b,x,y);ll t=x;x=y;y=t-a/b*y;return r;
}
bool jie(ll a,ll b,ll c,ll &x,ll &y)
{ll r=ex_gcd(a,b,x,y);if(c%r!=0) return 0;ll zz=c/r;x*=zz;y*=zz;if(x<0&&y<0) return 0;ll bb=b/r;ll aa=a/r;if(x<0&&y>0){ll t=-1*x/bb;if(x+bb*t<0) t++;x=x+bb*t;y=y-aa*t;if(y>=0) return 1;else return 0;}else if(x>0&&y<0){ll t=y/aa;if(y-aa*t<0) t--;x=x+bb*t;y=y-aa*t;if(x>=0) return 1;else return 0;}return 1;
}
ll a,b,n,x,y;
int main()
{while(~scanf("%lld%lld%lld",&a,&b,&n)){x=0;y=0;if(jie(a,b,n,x,y)){printf("Yes\n");//printf("%lld %lld\n",x,y);
        }else{printf("No\n");}}return 0;
}

#include <bits/stdc++.h>using namespace std;
const int N = 1010;
int main()
{int t,n,a[N],len,ma;scanf("%d",&t);while(t--){len=0;ma=0;scanf("%d",&n);for(int i=0;i<n;i++)scanf("%d",&a[i]);for(int i=0;i<n;i++){if(a[i]==8){len++;ma=max(ma,len);}else{len=0;}}printf("%d\n",ma);}return 0;
}
/*
10
10
8 8 8 7 6 8 8 8 8 8
6
5 8 8 2 3 4
*/

#include<bits/stdc++.h>
using namespace std;int is_prime(int n)
{for(int i=2;i<=sqrt(n);i++){if(n%i==0)return 0;}return 1;
}int main()
{int n,sum;while(~scanf("%d",&n),n){sum=0;for(int i=2;i<=n/2;i++){if(is_prime(i)&&is_prime(n-i))sum++;}printf("%d\n",sum);}return 0;
}

#include<bits/stdc++.h>
using namespace std;
#define ll long long
int x,y,n,ans,sum,f;
int a[10000+10];
int cmp(int a,int b)
{return a>b;
}
int main()
{while(~scanf("%d%d",&n,&x)){ans=sum=f=0;for(int i=0;i<n;i++){scanf("%d",&a[i]);}sort(a,a+n,cmp);for(int i=0;i<n;i++){sum+=a[i];ans++;if(sum>=x){f=1;break;}}if(f) printf("%d\n",ans);else printf("-1\n");}return 0;
}

#include <bits/stdc++.h>using namespace std;
vector<string> dict;
map<string,bool> mp;
int f;
int main()
{int cas=1;string s,buf;while (getline(cin,s)){dict.clear();mp.clear();//memset(dict,0,sizeof(dict));f=0;for(int i=0;i<s.length();i++)if (isalpha(s[i])){ //有单词即大小写字母标记一下f=1;}else s[i]=' ';//非单词（大小写字母）用空格代替 方便后续stringstream使用
        stringstream ss(s);while (ss>>buf){//mp.clear();if(mp[buf]==true)continue;else{dict.push_back(buf);mp[buf]=true;}//cout<<"buf = "<<' '<<buf<<endl;
        }vector <string> ::iterator it;printf("Case %d:\n",cas++);if(f){for(it=dict.begin(); it!=dict.end(); it++)cout<<*it<<endl;}else{puts("NO");}}return 0;
}

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>
#include<time.h>
#define mod 1000000009
#define ll long long
ll dp[10000+10];
ll m;
void predeal( )
{dp[0] = 1;//注意初始化0级dp[1]=1,dp[2]=2;for( int i=3;i<=10000;i++)for(int j=1;j<=i;j++)dp[i] = (dp[i]%mod + dp[i-j]%mod)%mod;//一边取模，否则炸
}
int main()
{predeal( );while(~scanf("%lld",&m)){printf("%lld\n",dp[m]%mod);}return 0;
}

#include<bits/stdc++.h>using namespace std;struct node
{int a,b;
}a[50005];int n,tot=0;
int q[50005],p[50005];
bool cmp(const node &a,const node &b)
{if(a.a!=b.a) return a.a<b.a;return a.b<b.b;
}
void ef(int i)
{int l=1,r=tot;while(l<r){int mid=(l+r)/2;if(a[i].a>p[mid]) l=mid+1;if(a[i].a<=p[mid]) r=mid;}if(a[i].b>p[l]) p[l]=a[i].b;
}
int main()
{scanf("%d",&n);for(int i=1;i<=n;i++){scanf("%d%d",&a[i].a,&a[i].b);}sort(a+1,a+n+1,cmp);q[++tot]=a[1].a;p[tot]=a[1].b;for(int i=2;i<=n;i++){if(a[i].a<=p[tot])ef(i);else{q[++tot]=a[i].a;p[tot]=a[i].b;}}printf("%d\n",tot);for(int i=1;i<=tot;i++){printf("%d %d\n",q[i],p[i]);}
}

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<string.h>
#include<time.h>
#define mod 609929123
#define ll long long
ll n,a[20000+100],sum[20000+100];
ll ans;
int main()
{scanf("%lld",&n);sum[0]=0;for(ll i=1;i<=n;i++){scanf("%lld",&a[i]);sum[i]=sum[i-1]+a[i];}ans=0;for(ll i=1; i<=n; i++){for(ll j=i+1; j<=n; j++){ans += ( a[i] * a[j]* ( sum[n]-sum[j] )%mod )%mod;//printf("ans = %d\n",ans);
        }}printf("%lld\n",ans % mod);
}

#include<bits/stdc++.h>using namespace std;char a[105][105];
char d[4]={ '+','-','*','/' };int main()
{int t,n;scanf("%d",&t);while(t--){scanf("%d",&n);int flag=0;int x=0;for(int i=0; i<n; i++){if(x%2==0){for(int j=i; j<n; j++){a[j][j-i]=d[flag%4];flag++;}}else{for(int j=n-1; j>=i; j--){a[j][j-i]=d[flag%4];flag++;}}x++;}for(int i=0; i<n; i++){for(int j=0; j<n; j++){if(j<=i)printf("%c%c",a[i][j],j==i?'\n':' ');}}printf("\n");}
}