#include <bits/stdc++.h>
int main() {
  int a, b;
  char s[11];
  int i;
  int suitti = 0;
  int save;
  scanf("%d%d%s", &a, &b, s);
  if (s[a] == '-') {
    for (i = 0; i < a; i++) {
      if (s[i] == '-') suitti++;
    }
    for (i = a + 1; i < a + b + 1; i++) {
      if (s[i] == '-') suitti++;
    }
  } else {
    save = 1;
    printf("No");
  }
  if (suitti > 0)
    printf("No");
  else if (save != 1)
    printf("Yes");
  return 0;
}
