program diaper;
 
const
    MAXN = 100;
 
var
    K, N, i, milk, food : LongInt;
    F : array[0..MAXN-1] of longint;
    B : array[0..MAXN-1] of char; (*per il carattere blank tra il numero e il tipo di pasto*)
    T :  array[0..MAXN-1] of char;
begin
 
    (*assign(input,  'input.txt');  reset(input);
    assign(output, 'output.txt'); rewrite(output);*)
 
 
    ReadLn(N);
 
    for i:=0 to N-1 do  readln (F[i],B[i],T[i]);
 
    K := 0; milk:=0; food:=0;
 
    for i:=0 to N-1 do
          begin
            if T[i]='M' then milk:=milk +F[i];
 
            if T[i]='B' then food:=food +F[i];
 
            if milk>=50 then begin if i<N-1 then begin K:=K+1; milk:=milk-50;end; end
                        else
                          if food>=80 then begin if i<N-1 then begin K:=K+1; food:=food-80;end; end;
 
         end;                    
 
    WriteLn(K);
 
end.

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NQoxNTAgTQoxIEIKMSBCCjEgQgoxIEI=

5
150 M
1 B
1 B
1 B
1 B