JAVA - Algorithms - Math.pow by every base.digits

For example :  

A = 1, Z = 26 , Find AB =?

YZ = 25*(26^1) + 26*(26^0)
XYZ = 24*(26^2) + 25*(26^1) + 26*(26^0)


class Solution {
public int titleToNumber(String columnTitle) {
int result = 0;
for(int i = 0 ;i < columnTitle.length();i++){
result += (columnTitle.charAt(i) - 64) * Math.pow(26, columnTitle.length() - i -1 );
}

return result;
}

} 

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