ls=[0,1,2,3,4,5,6,7,8,9]
a,b=[int(s) for s in input().split()]
S=input()
if S[a]=='-':
  for i in range(a):
    if not(S[i] in ls):
      print('No')
      break
  else:
    for j in range(b):
      if not(S[a+j+1] in ls):
        print('No')
        break
    else:
      print('Yes')
else:
  print('No')