#include <bits/stdc++.h>
using namespace std;
using uint = unsigned int;
using ll = long long;
using ull = unsigned long long;
const int MOD = 1e9 + 7;
void solve() {}
int main() {
  int A, B;
  string s;
  cin >> A >> B >> s;
  A--;
  bool ok = true;
  for (int i = 0; i < (int)s.size(); ++i) {
    if (i == A + 1) {
      if (s[i] != '-') {
        ok = false;
      }
    } else {
      if ((int)s[i] < 0 && (int)s[i] > 9) {
        ok = false;
      }
    }
  }
  if (ok) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
  return 0;
}
