from collections import defaultdict,deque
import sys,heapq,bisect,math,itertools,string,queue,datetime
sys.setrecursionlimit(10**8)
INF = float('inf')
mod = 10**9+7
eps = 10**-7
def inpl(): return list(map(int, input().split()))
def inpl_s(): return list(input().split())

A,B = inpl()
S = input()

def solve():
	if A+B+1 != len(S):
		return False

	for i in range(A+B+1):
		if i < A:
			if S[i] == '-':
				return False

		if A<= i < B:
			if S[i] != '-':
				return False

		if B <= i:
			if S[i] == '-':
				return False

	return True

if solve():
	print('Yes')
else:
	print('No')
