题解 | #矩阵乘法计算量估算#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    const n = parseInt(await readline());
    const nums = [];
    for(let i = 0; i < n; i++){
        nums.push((await readline()).split(" ").map(Number));
    }
    const str = await readline();
    const stack = [];
    let cnt = 0;
    let index = 0;
    for(const c of str){
        // console.log(stack,cnt)
        if(c === "("){
            continue;
        }else if(c === ")"){
            let second = stack.pop();
            let first = stack.pop();
            cnt += first[0] * first[1] * second[1];
            stack.push([first[0],second[1]]);
        }else{
            // stack.push(nums[c.charCodeAt()-"A".charCodeAt()]);
            stack.push(nums[index++]);//为了摆脱对字母的依赖
        }
    }
    console.log(cnt);
}()