#include <bits/stdc++.h>
int main(void) {
  uint32_t a, b;
  std::string s;
  std::cin >> a >> b >> s;
  int32_t pos = -1;
  uint32_t idx = 0;
  for (auto c : s) {
    if (!(('0' <= c && c <= '9') || c == '-')) goto NO;
    if (c == '-') {
      if (idx == 0) goto NO;
      if (pos != -1) goto NO;
      pos = idx;
    }
    idx++;
  }
  if (pos == -1) goto NO;
  if (static_cast<uint32_t>(pos) == s.size() - 1) goto NO;
  std::cout << "Yes" << std::endl;
  return 0;
NO:
  std::cout << "No" << std::endl;
  return 0;
}
