a = input()
b = input()
tong = 0
chu_cai = "abcdefghijklmnopqrstuvwxyz"
for c in chu_cai:
dem_a = 0
dem_b = 0
for i in a:
if i == c:
dem_a += 1
for j in b:
if j == c:
dem_b += 1
tong += min(dem_a, dem_b)
print(tong)