A,B = map(int,input().split())

S = input()

for i in range (A):
  if S[i] == '-':
    print("No")
    exit()
  else:
    continue
for j in range(B,A+B+1):
  if j == B and S[j] != '-':
    print("No")
    exit()
  elif S[j] == '-':
    print("No")
    exit()
    
print("Yes")