def compute_failure(t):
    n = len(t)
    fail = [0] * n
    j = 0
    for i in range(1, n):
        while j > 0 and t[i] != t[j]:
            j = fail[j-1]
        if t[i] == t[j]:
            j += 1
            fail[i] = j
        else:
            fail[i] = 0
    return fail

def main():
    import sys
    s = sys.stdin.readline().strip()
    t = sys.stdin.readline().strip()
    m = len(t)
    n = len(s)
    
    if m == 0:
        print(0)
        return
    if m > n:
        print(0)
        return
    
    failure = compute_failure(t)
    INF = float('inf')
    
    # Initialize DP table
    dp = [[INF] * (m + 1) for _ in range(n + 1)]
    dp[0][0] = 0
    
    for i in range(n):
        for j in range(m + 1):
            if dp[i][j] == INF:
                continue
            
            # Option 1: Insert a '.' after current character
            if dp[i+1][0] > dp[i][j] + 1:
                dp[i+1][0] = dp[i][j] + 1
            
            # Option 2: Do not insert, process current character
            current_j = j
            c = s[i]
            while current_j > 0 and c != t[current_j]:
                current_j = failure[current_j - 1]
            if c == t[current_j]:
                current_j += 1
            else:
                current_j = 0
            
            if current_j < m:
                if dp[i+1][current_j] > dp[i][j]:
                    dp[i+1][current_j] = dp[i][j]
    
    min_ans = min(dp[n][:m])
    if min_ans == INF:
        print(-1)
    else:
        print(min_ans)

if __name__ == "__main__":
    main()