#include "bits/stdc++.h" using namespace std; #define intt long long #define fi first #define se second const intt mxN = 2e5 + 5; const intt LG = 20; const intt inf = 1e18; intt x, n; void _() { cin >> x >> n; intt cur = x; for(intt i = 0; i < n; i++) { intt v; cin >> v; cur = x + (cur - v); cur = max(cur, x); } cout << cur << endl; } int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL); intt t = 1, buu = 1; // cin >> t; while(t--){ // cout << "Case #" << buu++ << ": "; _(); } }