#include <cstdio>
#include <iostream>
#include <string>
#include <cstring>
using namespace std;
int main(){int n,m;cin>>n>>m;if(n%m!=0||n==m) cout<<-1<<endl;else {cout<<m<<' '<<n-m<<endl;}return 0;
}

#include <cstdio>
#include <iostream>
#include <string>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;
struct node{long long x,y;
}s[200005];unsigned long long area(node a,node b,node c){unsigned long long sum=abs(a.x*b.y+b.x*c.y+c.x*a.y-a.x*c.y-b.x*a.y-c.x*b.y);return sum;}
int main()
{int n,m;cin>>n;for(int i=0;i<n;i++) cin>>s[i].x>>s[i].y;unsigned long long minx=1e19;for(int i=0;i<n-2;i++) minx=min(minx,area(s[i],s[i+1],s[i+2]));minx=min(minx,area(s[0],s[n-1],s[n-2]));minx=min(minx,area(s[0],s[1],s[n-1]));cout<<minx<<endl;
}

#include <cstdio>
#include <iostream>
#include <string>
#include <algorithm>
#include <cstring>
using namespace std;
struct node{int a,b;
}s[200005];int cmp(node x,node y){if(x.b==y.b) return x.a<y.a;return x.b<y.b;}
int main()
{int n,m=0;int t=0;int cnt[200005];cin>>n;for(int i=0;i<n;i++) cin>>s[i].a>>s[i].b;sort(s,s+n,cmp);int sw=s[0].b;for(int i=1;i<n;i++){if(s[i].a>sw){cnt[t++]=sw;sw=s[i].b;}}cnt[t++]=sw;cout<<t<<endl;cout<<cnt[0];for(int i=1;i<t;i++) cout<<' '<<cnt[i];
}

#include <cstdio>
#include <iostream>
#include <string>
#include <cstring>
using namespace std;
int main(){string a,b;string c;int vis[200005];int n=0,m=-1;cin>>a>>b;memset(vis,0,sizeof(vis));for(int i=0;i<a.length();i++){if(a[i]!=b[i]){m=i;for(int j=i+1;j<a.length();j++){if(a[i]==b[j]) vis[n++]=j;}break;}}if(m==-1){cout<<"YES"<<endl;return 0;}for(int i=0;i<n;i++){c=a;int sw=1;int ss=(m+vis[i])/2;if((m+vis[i])%2==0) sw=0;for(int j=ss;j>=m;j--){swap(c[j],c[ss+(sw++)]);}if(c==b){cout<<"YES"<<endl;return 0;}}cout<<"NO"<<endl;return 0;
}

Select Code
#include <iostream>
#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<queue>
using namespace std;
int a[200005];
int main()
{int n,i,x;cin>>n;while(n--){cin>>x;a[x]++;}int sum=0;for(i=1;i<=200001;i++){if(a[i]){sum+=a[i]/2;}}cout<<sum/2<<endl;return 0;
}