function solve(input) {
    let sequences = input.split(/\s+/);
    let sum = 0;
    const isLowerCase = (string) => /^[a-z]*$/.test(string);

    const isUpperCase = (string) => /^[A-Z]*$/.test(string);

    for (let el of sequences) {
        let result = 0;
        let firstChar = el.charAt(0);
        let firstCharPosition = el.toLowerCase().charCodeAt(0) - 96;
        let lastChar = el.charAt(el.length - 1);
        let lastCharPosition = el.toLowerCase().charCodeAt(el.length - 1) - 96;
        let numberPart = Number(el.substring(1, el.length - 1));

        if(isUpperCase(firstChar)){
            result = numberPart/firstCharPosition;
            sum += result;
        }
        if(isLowerCase(firstChar)){
            result = numberPart * firstCharPosition;
            sum += result;
        }
        if(isUpperCase(lastChar)){
            sum -= lastCharPosition;
        }
        if(isLowerCase(lastChar)){
            sum += lastCharPosition;
        }
    }
    console.log(sum.toFixed(2));
}
solve('A12b s17G');