s = 'aaaabbbccww'
index = 1
b = ''
for i in range(0 , len(s)-1):
    if s[i] == s[i+1]:
        index +=1
    elif s[i] != s[i+1]:
        b += s[i] + str(index)
        index = 1
else:
    b += s[-1] + str(index)
print(b)