#Postal Code
A,B=map(int,input().split())
d=["0","1","2","3","4","5","6","7","8","9"]
S=input()
total=0
for i in range(A):
    if S[i] in d:
        pass
    else:
        total=1
S=S[A:]
if S[0]!="-":
    total=2
S=S[1:]
for i in range(B):
    if S[i] in d:
        pass
    else:
        total=3
if total==1:
    print("No")
else:
    print("Yes")