문제
풀이
#include <algorithm>
#include <iostream>
#include <utility>
#include <vector>
using namespace std;
void solve(void) {
int n, m; cin >> n >> m;
vector<pair<int, int>> v(m);
for (int i=0; i<m; i++) cin >> v[i].first >> v[i].second;
sort(v.begin(), v.end());
int ans = 0;
for (int i=1; i<m; i++) {
if (v[i].first >= n) break;
ans += n - v[i].first;
}
cout << ans;
}
int main(void) {
ios::sync_with_stdio(false);
cin.tie(nullptr);
solve();
return 0;
}