#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const double PI = 3.14159265358979;
void solve() {
  int a, b;
  string s;
  cin >> a >> b >> s;
  try {
    int i = stoi(s.substr(0, a));
    i = stoi(s.substr(a, b));
  } catch (...) {
    cout << "No";
    return;
  }
  cout << ((s[a] == '-') ? "Yes" : "No");
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  solve();
  return 0;
}
