#include<iostream>
using namespace std;
int main(){
	long long x, n, a, b, sum = 0;
	cin >> x >> n;
	for (int i = 1; i <= n; i++){
		cin >> a >> b;
		long long p = 1;
		for (int j = 1; j <= b; j++)
			p = p * x;
		sum = sum + a * p;
	}
	cout << sum;
	return 0;
}

#include <iostream> using namespace std; int main(){ int x,n; cin >> x >> n; long long sum = 0; for(int i = 1; i <= n; i++) { int a,b; cin >> a >> b; long long cnt = 1; for(int j = 1; j <= b;j ++) { cnt *= x; } sum += a * cnt; } cout << sum; return 0;

}