Alphabet Shift Encryption – String

Alphabet Shift Encryption – String: The program must accept a string S containing only alphabets and L integers as the input (where L is the length of S). For each integer X among the L integers, the program must encrypt the first P alphabets in the string, where P represents the position of the integer X. To encrypt an alphabet, the alphabet must be replaced by the following X^th alphabet with the same case in the English alphabet set. Finally, the program must print the modified string S as the output.
Note: The English alphabet set must be considered in a cyclic fashion for finding the X^th alphabet in the encryption.

Boundary Condition(s):
1 <= Length of S <= 100
1 <= Each integer value <= 1000

Input Format:
The first line contains S.
The second line contains L integers separated by a space.

Output Format:
The first line contains the modified string S.

Example Input/Output 1:
Input:
big
2 1 6

Output:
kpm

Explanation:
Here S = big.
The length of S is 3 and the three integers are 2, 1 and 6.
X = 2 -> After encrypting the first alphabet, the string becomes dig.
X = 1 -> After encrypting the first 2 alphabets, the string becomes ejg.
X = 6 -> After encrypting the first 3 alphabets, the string becomes kpm.
So kpm is printed as the output.

Example Input/Output 2:
Input:
SkillRack
8 7 6 5 3 2 1 4 9

Output:
LvmjeHopt

s=list(input().strip())
l=list(map(int,input().split()))
for i in range(0,len(l)):
    for j in range(0,i+1):
        for k in range(1,l[i]+1):
            a=ord(s[j])+1
            if a==123 or a==91:
                a-=26
            s[j]=chr(a)
print(''.join(s))