#include <bits/stdc++.h>   using namespace std;   int n, m, l, r, x;   string s;   int main() {     cin >> n >> m;     r = 0;     l = n + 1;     for (int i = 0; i < m; ++i) {       cin >> s;       cin >> s;       cin >> s;       if (s ==  left ) {         cin >> s >> x;         l = min(l, x);       } else {         cin >> s >> x;         r = max(r, x);       }     }     if (l - r - 1 <= 0)       cout << -1 << endl;     else       cout << l - r - 1 << endl;   }   