Missed pill in a dose of the morning after pills

Patient: Dear doctor I bought the morning after pill from my local clinic because I thought I might be pregnant and I’m too young to be pregnant. I took all 5 pills and a gravol for the first dose, when taking the second dose one of the pills dropped down the sink drain so I still took the 4 pills I had left and gravol again. The only gave me enough for two doses and I’m just wondering will it still prevent me from getting pregnant because I took 9 pills and not 10 of the morning after pill.