#define _CRT_SECURE_NO_WARNINGS
#include"bits/stdc++.h"
#ifdef _DEBUG
#define DBG(n) n
#else
#define DBG(n)
#endif
#define INF          1e9
#define INFLL        1e18
#define EPS          1e-9
#define MOD          1000000007
#define REP(i,n)     for(ll i=0,i##_len=(n);i<i##_len;++i)
#define REP1(i,n)    for(ll i=1,i##_len=(n);i<=i##_len;++i)
#define REPR(i,n)    for(ll i=(n)-1;i>=0;--i)
#define REPR1(i,n)   for(ll i=(n);i>0;--i)
#define REPC(i,obj)  for(auto i:obj)
#define ALL(obj)     (obj).begin(),(obj).end()
#define SETP(n)      cout<<fixed<<setprecision(n)
#define VV(T,h,w)    move(vector<vector<T>>(h,move(vector<T>(w))))
#define VVI(T,h,w,i) move(vector<vector<T>>(h,move(vector<T>(w,i))))
using namespace std;
using ll = long long;
template<typename T = ll>inline T in() { T ret; cin >> ret; return ret; }

int main()
{
	ll a = in(), b = in();
	string s; cin >> s;
	string head = s.substr(0, a), foot = s.substr(a + 1);
	cout << (all_of(ALL(head), isdigit) && s[a] == '-' && all_of(ALL(foot), isdigit) ? "Yes" : "No") << endl;
}