#include <bits/stdc++.h>
using namespace std;
template <class T>
inline void checkmin(T &a, T b) {
  if (b < a) a = b;
}
template <class T>
inline void checkmax(T &a, T b) {
  if (b > a) a = b;
}
template <class T>
inline T abs(T x) {
  return x < 0 ? -x : x;
}
template <class T>
inline T extgcd(T a, T b, T &x, T &y) {
  int d = a;
  if (b != 0) {
    d = extgcd(b, a % b, y, x);
    y -= (a / b) * x;
  } else {
    x = 1;
    y = 0;
  }
  return d;
}
template <class T>
inline T mypow(T n, T k) {
  T res = 1;
  for (T i = 0; i < k; ++i) res *= n;
  return res;
}
template <class T>
inline T mod_pow(T x, T n, T mod) {
  T res = 1;
  while (n) {
    if (n & 1) res = res * 1LL * x % mod;
    x = x * 1LL * x % mod;
    n >>= 1;
  }
  return res;
}
template <class T>
inline T add(int *b, int i, T x, int N) {
  while (i <= N) {
    *(b + i) += x;
    x += (x & (-x));
  }
}
template <class T>
inline T getsum(int *b, int i) {
  T res = 0;
  while (i > 0) {
    res += *(b + i);
    i -= (i & (-i));
  }
  return res;
}
template <class T>
inline void add_mod(T &a, int mod = -1) {
  if (mod == -1) mod = 1e9 + 7;
  while (a >= mod) a -= mod;
  while (a < 0) a += mod;
}
const int maxn = 1e5 + 10;
const long long mod = 1e9 + 7;
const int inf = 2147483647;
const int sigma_size = 26;
const long long LLMAX = 0x7fffffffffffffffLL;
const long long LLMIN = 0x8000000000000000LL;
const int INF = 2147483647;
const int IMIN = 0x80000000;
const long long MOD = 1000000007LL;
const double pi = acos(-1.0);
inline int pdt(int x, int y) {
  int ret;
  __asm__ __volatile__("\tmull %%ebx\n\tdivl %%ecx\n"
                       : "=d"(ret)
                       : "a"(x), "b"(y), "c"(MOD));
  return ret;
}
long long gcd(long long a, long long b, long long *x, long long *y) {
  long long tx, ty;
  long long g;
  if (b > a) return gcd(b, a, y, x);
  if (b == 0) {
    *x = 1;
    *y = 0;
    return a;
  }
  g = gcd(b, a % b, &tx, &ty);
  *x = ty;
  *y = tx - floor(a / b) * ty;
  return g;
}
long long binomialCoeff(int n, int k) {
  long long C[k + 1];
  memset(C, 0, sizeof(C));
  C[0] = 1;
  for (int i = 1; i <= n; i++) {
    for (int j = min(i, k); j > 0; j--) C[j] = (C[j] + C[j - 1]) % mod;
  }
  return C[k] % mod;
}
long long dp[1010][1010];
long long inv[4000010];
int init() {
  inv[1] = 1;
  for (int i = 2; i < 4000010; i++) {
    inv[i] = (MOD - MOD / i) * 1ll * inv[MOD % i] % MOD;
  }
}
long long getdp(int a, int b, int k) {
  if (b >= k) return b;
  return dp[a][b];
}
int main() {
  ios_base::sync_with_stdio(0);
  int a, b;
  string s;
  cin >> a >> b >> s;
  int i = 0;
  bool flag = 1;
  if (s.size() != a + b + 1) {
    cout << "No" << endl;
    return 0;
  }
  while (i < s.size()) {
    if (i == a && s[i] == '-' || (s[i] >= '0' && s[i] <= '9'))
      ;
    else
      flag = 0;
    i++;
  }
  if (!flag)
    cout << "No" << endl;
  else
    cout << "Yes" << endl;
  return 0;
}
