program main implicit none type pair integer::x,y end type pair integer::N,K,i,j,tmp, shuffle=1 integer::num(100)=(/(i,i=1,100)/) integer::group(100) type(pair)::bar(1000) data group/100*0/ read *,N,K if(K.eq.0) then print '(i0)', 1 else read *,bar(1:K) end if ! print *, bar(1:K) do i=1,K tmp = num(bar(i)%x) num(bar(i)%x) = num(bar(i)%y) num(bar(i)%y) = tmp end do do i=1,N if(group(i).eq.0) then j = 0 tmp = i do tmp = num(tmp) group(tmp) = 1 j = j + 1 if(tmp.eq.i) exit end do shuffle = lcm(shuffle, j) end if end do print '(i0)', shuffle ! print '(i0," ")',(num(i),i=1,N) contains function lcm(a,b) result(c) integer,intent(in)::a,b integer::c c = (a*b)/gcd(a,b) end function lcm recursive function gcd(a,b) result(c) integer::a,b,c if(b.eq.0) then c = a else c = gcd(b,MOD(a,b)) end if end function gcd end program main