const inst: number[] = require("fs").readFileSync(0).toString().trim().split(" ").map(Number);
const steps: number = inst.length - 1;

const force: number[][] = [
    [1,2,2,2,2],
    [0,1,3,4,3],
    [0,3,1,3,4],
    [0,4,3,1,3],
    [0,3,4,3,1]
];

let dp: number[][][] = Array.from( {length: 2}, (_, i) => 
        Array.from({length: 5}, () => 
        Array.from({length: 5}, () =>
                    i===1 ? 0 : Infinity
        )
    )
);

let currentIsZero: boolean = true;

for(let i=steps-1; i >= 0; i--) {
    const current: number = currentIsZero ? 0 : 1;
    const next: number = currentIsZero ? 1 : 0;
    const target: number = inst[i];

    for(let l=0; l<5; l++) {
        for(let r=0; r<5; r++) {
            const moveLeft: number = dp[next][target][r] + force[l][target];
            const moveRight: number = dp[next][l][target] + force[r][target];
            dp[current][l][r] = Math.min(moveLeft, moveRight);
        }
    }

    currentIsZero = !currentIsZero;
}

console.log(dp[currentIsZero ? 1 : 0][0][0]);