#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstdlib>
#include<cstring>
#include<algorithm>
using namespace std;
#define ll long long
#define N 100010
#define lson tree[k].ch[0]
#define rson tree[k].ch[1]
char getc(){char c=getchar();while ((c<'A'||c>'Z')&&(c<'a'||c>'z')&&(c<'0'||c>'9')) c=getchar();return c;}
int gcd(int n,int m){return m==0?n:gcd(m,n%m);}
int read()
{int x=0,f=1;char c=getchar();while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}while (c>='0'&&c<='9') x=(x<<1)+(x<<3)+(c^48),c=getchar();return x*f;
}
int n,r,c,root,cnt;
ll ans;
struct data
{int x,y;bool operator <(const data&a) const{return x<a.x;}
}a[N];
struct data2{int ch[2],x,p,s,lazy;ll ans;
}tree[N<<1];
void up(int k)
{tree[k].s=tree[lson].s+tree[rson].s+1;tree[k].ans=tree[lson].ans+tree[rson].ans+1ll*tree[k].p*(tree[lson].s+1)*(tree[rson].s+1);
}
void move(int &k,int p)
{int t=tree[k].ch[p];tree[k].ch[p]=tree[t].ch[!p],tree[t].ch[!p]=k,up(k),up(t),k=t;
}
void build(int &k,int l,int r)
{if (l>r) return;k=++cnt;int mid=l+r>>1;tree[k].x=mid,tree[k].p=0;build(lson,l,mid-1);build(rson,mid+1,r);up(k);
}
void update(int k,int x)
{tree[k].lazy+=x;tree[k].p+=x;tree[k].ans+=1ll*x*tree[k].s*(tree[k].s+1)/2;
}
void down(int k)
{update(lson,tree[k].lazy);update(rson,tree[k].lazy);tree[k].lazy=0;
}
void modify(int &k,int x)
{down(k);if (tree[k].x==x) tree[k].p=0;else if (tree[k].x<x) modify(rson,x),move(k,1);else modify(lson,x),move(k,0);up(k);
}
int main()
{
#ifndef ONLINE_JUDGEfreopen("bzoj2658.in","r",stdin);freopen("bzoj2658.out","w",stdout);const char LL[]="%I64d\n";
#elseconst char LL[]="%lld\n";
#endifr=read(),c=read(),n=read();for (int i=1;i<=n;i++) a[i].x=read(),a[i].y=read();ans=1ll*r*(r+1)*c*(c+1)/4;sort(a+1,a+n+1);build(root,1,c);int x=0;for (int i=1;i<=r;i++){update(root,1);while (a[x+1].x==i){x++;modify(root,a[x].y);}ans-=tree[root].ans;}cout<<ans;return 0;
}
//ans=Σpi*(sl+1)*(sr+1)