#include <bits/stdc++.h>
using namespace std;
int main() {
  int A, B, judge;
  string S;
  cin >> A >> B >> S;
  for (int i = 0; i < A; i++) {
    if (S[i] >= '0' && S[i] <= '9')
      judge = 0;
    else
      judge = 1;
  }
  if (S[A] != '-') judge = 1;
  for (int i = A + 1; i < B; i++) {
    if (S[i] >= 0 && S[i] <= 9) {
      ;
    } else
      judge = 1;
  }
  switch (judge) {
    case 0:
      puts("Yes");
      break;
    case 1:
      puts("No");
      break;
  }
  return (0);
}
