def edit_distance(s,t):
    distance = []
    for x in range (0,len(s)):
        distance.append([])
        for y in range (0,len(t)):
            distance[x].append([])
    for i in range (0,len(s)):
        distance[i][0] = i
    for j in range (0,len(t)):
        distance[0][j] = j
    for j in range (1,len(t)):
        for i in range (1,len(s)):
            if s[i] == t[j]:
                distance[i][j] = distance[i-1][j-1]
            else:
                distance[i][j] = min(distance[i-1][j] + 1,distance[i][j-1] + 1,distance[i-1][j-1] +1)
    return distance[len(s)-1][len(t)-1]