Помогите пожалуйста решить 1) дано натуральное число

1) Program Pr1; uses crt; var stroka: string; i,k: integer; Beginclrscr; writeln ('Vvedite chislo'); readln (stroka); k: =0; for i: =length (stroka) downto 1 do if stroka[i]='3' then k: =i; writeln (k); end.2) Program Pr2; uses crt; var stroka: string; i,k,x,y: integer; Beginclrscr; readln (stroka); y: =0; for i: =length (stroka) downto (length (stroka) -1) do begin val (stroka[i],k,x); y: =y+k; end; writeln (y); end. 3) Program Pr2; uses crt; var stroka: string; i,y,k: integer; mas: array[byte] of integer; Beginclrscr; readln (stroka); for i: =1 to length (stroka) do begin val (stroka[i],y,k); mas[i]: =y; end; k: =0; for i: =1 to length (stroka) do if mas[i]>k then k: =mas[i]; writeln (k); end.4) Program Pr2; uses crt; var stroka,tmp: string; Beginclrscr; readln (stroka); {1-oe predlojenie}readln (tmp); {2-oe predlojenie}delete (stroka,1,length (tmp); stroka: =tmp+stroka; writeln (stroka); end.5) Program Pr2; uses crt; var mas: array[byte] of integer; i,n,f: integer; Beginclrscr; readln (n); mas[1]: =1; mas[2]: =1; for i: =3 to n do mas[i]: =mas[i-1]+mas[i-2]; writeln (mas[n],' a'); {a}readln; for i: =1 to n do write (mas[i],'); {á}f: =0; {â}readln; for i: =1 to n do f: =f+mas[i]; if f mod 2=0 then writeln ('TRUE') else writeln ('FALSE'); end.