while(line = readline()) {
    console.log(validate(line))
}
function validate(str) {
    let valid = "NG"
    let validStr = str.length > 8
    let validRepeat = repeat(str)
    let validTypes = types(str)
    if(validStr && validRepeat && validTypes) {
        valid = "OK"
    }
    return valid
}
function types(str) {
    let num = 0
    if(/[a-z]/.test(str)) {
        num++
    }
    if(/[A-Z]/.test(str)) {
        num++
    }
    if(/[0-9]/.test(str)) {
        num++
    }
    if(/[^0-9a-zA-Z]/.test(str)) {
        num++
    }
    return num >= 3
}
function repeat(str) {
    const arr = []
    for(let i=0; i<str.length-2; i++) {
        const sub = str.substring(i, i+3)
        if(arr.indexOf(sub) >= 0) {
            return false
        } else {
            arr.push(sub)
        }
    }
    return true
}