ACdream 1213 Matrix Multiplication

#include <cstring>
#include <cstdio>
typedef long long LL;
const int mx=100010;
int edge[mx][2];
int cnt[mx];

int main() {
    int n,m;
    while(~scanf("%d%d",&n,&m)) {
        memset(cnt,0,sizeof(cnt));
        for(int i=1; i<=m; i++) {
            int u,v;
            scanf("%d%d",&u,&v);
            edge[i][0]=u;
            edge[i][1]=v;
            cnt[u]++;
            cnt[v]++;
        }
        LL ans=0;
        for(int i=1; i<=m; i++) {
            ans+=cnt[edge[i][0]];
            ans+=cnt[edge[i][1]];
        }
        printf("%lld\n",ans);
    }
    return 0;
}