import pandas as pd
df = pd.read_csv('AdjMarketPricesog.csv')
assets = df.InstrumentID.unique()

def intersection(lst1,lst2):
    return list(set(lst1) & set(lst2))
dictionary = {}
dates = []
for asset in assets:
    filtered_df = df[df['InstrumentID'] == asset]
    prices = filtered_df['Price'].tolist()
    if len(dates) == 0:
        dates = filtered_df['Date'].tolist()
        print(len(dates))
    else:
        dates1 = filtered_df['Date'].tolist()
        dates = intersection(dates, dates1)
    dictionary[asset] = prices
print(len(dates))