#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B, c;
  string S;
  char s;
  c = 0;
  cin >> A >> B >> S;
  for (int i = 0; i < A + B + 1; i++) {
    if (S.at(i) == 0, 1, 2, 3, 4, 5, 6, 7, 8, 9) {
      c++;
    }
  }
  s = S.at(A);
  if (s != '-') {
    c--;
  }
  if (c == A + B + 1) {
    cout << "Yes" << endl;
  } else {
    cout << "No" << endl;
  }
}
