#include <bits/stdc++.h>
using namespace std;
int a, b, d;
string c;
int main() {
  cin >> a >> b >> c;
  for (int i = 0; i < a + b + 1; i++) {
    if (i < a && int(c[i]) < int('9') + 1 && int(c[i]) > int('0') - 1) d++;
    if (i = a && c[i] == '-') d++;
    if (i > a && int(c[i]) < int('9') + 1 && int(c[i]) > int('0') - 1) d++;
  }
  if (d = a + b + 1)
    cout << "Yes";
  else
    cout << "No";
  cout << endl;
  return 0;
}
