#include <bits/stdc++.h>
using namespace std;
template <typename T1, typename T2>
inline void chkmin(T1 &x, T2 y) {
  if (x > y) x = y;
}
template <typename T1, typename T2>
inline void chkmax(T1 &x, T2 y) {
  if (x < y) x = y;
}
inline int readChar();
template <class T = int>
inline T readInt();
template <class T>
inline void writeInt(T x, char end = 0);
inline void writeChar(int x);
inline void writeWord(const char *s);
static const int buf_size = 4096;
inline int getChar() {
  static char buf[buf_size];
  static int len = 0, pos = 0;
  if (pos == len) {
    pos = 0, len = fread(buf, 1, buf_size, stdin);
  }
  if (pos == len) {
    return -1;
  }
  return buf[pos++];
}
inline int readChar() {
  int c = getChar();
  while (c <= 32) {
    c = getChar();
  }
  return c;
}
template <class T>
inline T readInt() {
  int s = 1, c = readChar();
  T x = 0;
  if (c == '-') s = -1, c = getChar();
  while ('0' <= c && c <= '9') x = x * 10 + c - '0', c = getChar();
  return s == 1 ? x : -x;
}
static int write_pos = 0;
static char write_buf[buf_size];
inline void writeChar(int x) {
  if (write_pos == buf_size)
    fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
  write_buf[write_pos++] = x;
}
template <class T>
inline void writeInt(T x, char end) {
  if (x < 0) writeChar('-'), x = -x;
  char s[24];
  int n = 0;
  while (x || !n) s[n++] = '0' + x % 10, x /= 10;
  while (n--) writeChar(s[n]);
  if (end) writeChar(end);
}
inline void writeWord(const char *s) {
  while (*s) writeChar(*s++);
}
struct Flusher {
  ~Flusher() {
    if (write_pos) fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
  }
} flusher;
const string FILENAME = "input";
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int a, b;
  cin >> a >> b;
  string s;
  cin >> s;
  if ((int)(s).size() != a + b + 1) {
    cout << "No\n";
    return 0;
  }
  if (s[a] != '-') {
    cout << "No\n";
    return 0;
  }
  for (int i = 0; i < a + b + 1; i++) {
    if (i != a) {
      if (s[i] < '0' || s[i] >= '9') {
        cout << "No\n";
        return 0;
      }
    }
  }
  cout << "Yes\n";
}
