# Uses python3
def editDistance(A, B):
    m = len(B)
    n = len(A)
#     Matrix = [[0 for x in range(w)] for y in range(h)] 
# https://stackoverflow.com/questions/6667201/how-to-define-a-two-dimensional-array-in-python
    D = [[0 for _ in range(m + 1)] for _ in range(n + 1)]
    
    for i in range(n + 1):
        D[i][0] = i
    
    for j in range(m + 1):
        D[0][j] = j
    
    # watch out here, range starts at 1!
    for j in range(1, m + 1):
        for i in range(1, n + 1):
            insertion = D[i][j - 1] + 1
            deletion = D[i - 1][j] + 1
            match = D[i - 1][j - 1]
            mismatch = D[i - 1][j - 1] + 1
            if A[i - 1] == B[j - 1]:
                D[i][j] = min(insertion, deletion, match)
            else:
                D[i][j] = min(insertion, deletion, mismatch)
    return D[n][m]


if __name__ == "__main__":
    print(editDistance(input(), input()))