#include <bits/stdc++.h>
int main(void) {
  char S[11];
  int A, B;
  int i, j = 0, k = 0;
  scanf("%d%d", &A, &B);
  scanf("%s", S);
  if (strlen(S) != A + B + 1) {
    printf("No\n");
    return 0;
  }
  for (i = 0; i < strlen(S); i++) {
    if ((S[i] >= '0') && (S[i] <= '9'))
      j++;
    else if (S[i] == '-')
      k++;
    else {
      printf("No\n");
      return 0;
    }
  }
  if (k == 1) {
    printf("Yes\n");
    return 0;
  } else {
    printf("No\n");
    return 0;
  }
}
