#include<bits/stdc++.h>

using namespace std;
struct node 
{
    long long p,c;
    bool operator<(node x){
        return x.c<c;
    }
}Q[1005];
long long n,m,x,y,op[1005],len;
long long num;
bool flag(){
    for(long long i=2;i<=n;i++)if(op[i]>=op[1])return 1;
    return 0;
}
stack<int> s;
signed main() {
    cin>>n>>m;
    while(m--){
        cin>>x>>y;
        op[x]++;
        if(x!=1)Q[len++]={x,y};
    }
    sort(Q,Q+len);
    while(flag()){
        x=Q[--len].p;
        y=Q[len].c;
        op[x]--;
        op[1]++;
        num+=y;
    }//通过计算得出的
    cout<<num;
    return 0;
}