seq='AACAGTTTGTGTGGGCATGAAGGCGGCTGGCGGAAACTGCCCGGCCACAGTTGGCCAGGGCTGCTGAGTGGCAGGAAAGAGACCCGGCTGGCCCCATGCGATGGGCTGAGCCCCCGGCATCACCTGAGCGACTGGTGGCTGGGCACCCATGACCATCTGCTGTTGGACGAGGGGCTGCTGACCCCAGAAGGACGGGAGGACAGCGCCCATTGCAACGTAACCTGGGAGAATGAAAAAGGAGAGTCAGGTGTTTCCCTGGTGTCCTGGGAAAGAAGGATGCATGGACTCAGGTAATTGACAGAAATGTATCAAGCACCAACTAAGTGCCAGACTGTGTGCCAGGGACTGGGGATGCCAAGATGAACAAGACAAAGTCCTTGCTGTCATAGAGCCTATATCCAGAGAAGTGGTCAGGGAAATCCTCTCTGAGGAGATGATCTGTAAGCAAAAACTAGAATGCTAGTAATCACATTTCTGTAGTTGCTAAAAGTTTCTAAAGTCTCATAGCCTCAGAAGCTGTGTGTCTCAGGGACAGGGCAGAAGGATGGAAGGCAGGCCTCCTGGGTTTTCTCCTTGCCTCCTCTTCCTGCTGCACTTAGGACCCTCTCAATTGCATAAGCTCTCTAAGAGTCTGACTCTTTGTGGTAAAACCAGGTTATAATACCTTCCTTCACAGGACTTAGGCAGTGTGCAGAGTGAGTAAGAATCTGAATGTTGGAGTTTTAGAGACCTAGGTTAAAATTCAAATGGCCACTTCTTATCTATGTAATTTGGGGAGCAGTTCTTAAATCTGTCTAGGG';
N=length(seq);
disp(N);
disp('bases');
Nstart = 0;
for i = 1: (N-2);
    if(seq(i) == 'A' & seq(i+1) == 'T' & seq(i+2) == 'G');
        Nstart = Nstart+1;
        start(Nstart) = i;
        disp(i);
        disp('position');
    end;
end;
disp(Nstart);
disp('codons start');
i = start(1);
do
    i = i+3;
until ((seq(i) == 'T' & seq(i+1) == 'A'& seq(i+2) == 'G')||(seq(i) == 'T' & seq(i+1) == 'A'& seq(i+2) == 'A')|| (seq(i) == 'T' & seq(i+1) == 'G'& seq(i+2) == 'A'));
disp(i);
disp('premier codon stop');
stop = i;
Naa = (stop-start(1))/3;
disp(Naa);
disp('d''acides aminees');