proc totient(word n) word:
    word tot, i;
    tot := n;
    i := 2;
    while i*i <= n do
        if n%i = 0 then
            while n%i = 0 do n := n/i od;
            tot := tot - tot/i
        fi;
        if i=2 then i:=1 fi;
        i := i+2
    od;
    if n>1 then
        tot - tot/n
    else
        tot
    fi
corp

proc main() void:
    word count, n, tot;
    bool prime;

    count := 0;
    writeln(" N  Totient  Prime");
    for n from 1 upto 25 do
        tot := totient(n);
        prime := n-1 = tot;
        if prime then count := count+1 fi;
        writeln(n:2, "  ", tot:7, "  ", if prime then "  Yes" else "   No" fi)
    od;
    writeln("Number of primes up to ",25:6,": ",count:4);
    for n from 25 upto 10000 do
        if totient(n) = n-1 then count := count+1 fi;
        if n=100 or n=1000 or n=10000 then
            writeln("Number of primes up to ",n:6,": ",count:4)
        fi
    od
corp